Air gauge system for tubing walls

ABSTRACT

An air gauge device for tubing is provided by having nozzles built into a special housing with a circular slot means. The slot for a tubing end is formed by a specially fabricated cylinder member being inserted concentrically within a sized hole in the housing. One nozzle discharges from the housing wall to one side of the slot while the opposing nozzle discharges from the internal cylinder side of the slot whereby air pressure will impinge upon each side of the wall of tubing inserted into the slot means. The connection of a calibrated pressure gauge or flow meter across the pressure supply lines to the internal opposing nozzles provides variation readings in wall thickness down to the order of 0.00025 inch.

United States Patent McLellan et a1.

[15] 3,681,974 [451 Aug. 8, 1972 [54] AIR GAUGE SYSTEM FOR TUBING WALLS[72] Inventors: Donald J. Mclellan, Exeter, Ontario; Roger B. Stotts,London, On-

2] Appl. No.: 87,694

[52] U.S. Cl ..73/37.5, 73/318 [51] Int. Cl. ..G0lb 13/06 [58] Field ofSearch ..73/37.5, 37.8, 37.9;

[56] References Cited UNITED STATES PATENTS Aller ..73/37.8 Rupley..73/37.9

Primary Examiner-Louis R. Prince Assistant Examiner-William A. Henry, 11Attorney-James R. Hoatson, Jr. and Philip T. Liggett ABSTRACT An airgauge device for tubing is provided by having nozzles built into aspecial housing with a circular slot means. The slot for a tubing end isformed by a specially fabricated cylinder member being insertedconcentrically within a sized hole in the housing. One nozzle dischargesfrom the housing wall to one side of the slot while the opposing nozzledischarges from the internal cylinder side of the slot whereby airpressure will impinge upon each side of the wall of tubing inserted intothe slot means. The connection of a calibrated pressure gauge or flowmeter across the pressure supply lines to the internal opposing nozzlesprovides variation readings in wall thickness down to the order of0.00025 inch.

7Clailm,2Drawingflgures PATENTEUAuc 8 I972 Figure A fr Inlet 1'! Column27 Air Inlet l/V VE/V TORS Donald J. McLal/an Roger 8. Starts ozi w A TTORNEYS AIR GAUGE SYSTEM FOR TUBING WALIS The present invention relatesto an air gauge device particularly adapted to measure variations inthickness for tubing walls. More specifically, the invention provides anapparatus suitable for the insertion of the end of a length of tubinginto circular slot means which is provided with internally constructedopposing noule means. The special unit may be part of a generallyconventional air gauging system.

Air gauging systems are not new and have been rather widely used to notevariations in material thicknesses, to measure differences in distancebetween two members, or to note hole diameter variations, etc.; however,none of the known devices have been especially adapted to measure tubingwall thickness or, more particularly, variations in thickness. Ingeneral, all air gauges operate on a similar principal, in that aregulated quantity of air from a nonle, or nozzles, is directed againsta work piece and as the clearance with respect to the work piece varies,then the escaping air flow varies and so does a pressure level upstreamfrom the nozzle. This pressure level, or an air flow rate, can be sensedor observed and used as a means for comparing clearance, a materialthickness, or a dimensional variation. Actually, where thicknessvariations are desired, there can be two spaced apart and opposing airnozzles utilized so that an object or given piece of material can beinserted between the two. The centering of the object between the twonozzles is not required since air pressures will compensate as positionvaries between the two outlets. A flow meter or single column gauge thathas a tee connection to tubing or passageways which, in turn, connectsto the two air supply lines to the nozzles will provide an accuratemeans for noting variations in thickness for the material, or an object,placed between two nozzles.

For the present invention, it may be considered a principal objectthereof to provide an apparatus particularly adapted to have opposingair nozzle means positioned each side of a circular slotted opening sothat thickness variations in tubular materials may be observed.

lt may also be considered an object of the invention to provide an airgauge device which has a removable cylinder member holding one of theair nozzle means such that modifications can be made in the device toaccommodate thin wall or thick wall tubing of a particular outsidediameter.

A still further object of the invention is to provide an air gaugingsystem for tubing that is of simple construction and suitable for notingthickness variations of less than one-one-thousandth of an inch.

Broadly, the present invention provides an apparatus system, formeasuring variations in thickness of tubing, which comprises incombination, a housing with a circular slot means therein from one endthereof for accommodating the non-touching insertion of tubing to bemeasured for thickness variations, said slot means formed by thepositioning of a removable cylinder member in a circular hole in saidhousing which is of predetermined diameter larger than said cylindermember, a fluid outlet port provided in and through said housing todischarge in said slot means, a fluid outlet port from said cylindermember directly opposite first said outlet port and of equal size as thelatter, fluid supply means to each of said opposing ports, a pressuretap means branching from each of said fluid supply means, with each ofthe presure tap means being joined and a single conduit means from thejuncture thereof connective to a gauging means providing a readingcorrelatable to the thickness of material inserted in said circular slotmeans.

Generally, the gauging system will use air and a conventional air columncan be used as the gauging means for the system; however, nitrogen orother inert gaseous medium could be used in connection with certaininstallation where there might be danger in the utilization of air.

It may also be pointed out that pressure gauge readings can be utilizedas well as fluid flow rate readings inasmuch as a pressure reading willbe correlatable to and vary responsive to the combination of backpressure sensed from each of the air nozzles that are in turn providingfor fluid flow to each side of the tubing wall. As hereinbefore noted,pressure readings are of particular advantage where there will beautomatic sensing means to note premure levels from a slip streamconnective with each of the air gauging nozzles. On the other hand, withregard to the visual observation of thickness variations of tubingwalls, there may be the utilization of an air column as a desirablemeans for noting variations in flow rate and, in turn, variations inmaterial thickness.

With respect to the housing design and the internal cylinder memberwhich provides for a resulting slot means to accommodate the insertionof a tubing end, there is preferably a removable cylinder member, alsoadjustable with respect to horizontal and longitudinal movement. Such adesign will permit accurate adjustment of the cylinder member withrespect to the housing in order to obtain direct opposing positioningfor each of the opposing air nozzles that will be discharging againstthe opposing faces of the tube end being inserted into the device. Apreferred design and construction also makes use of a port constructionwhereby there is an indention or cut-out zone around the periphery ofthe exterior end of each port means to in turn provide a nozfle type ofconstruction for respectively the air outlet from the housing and theair outlet from the cylinder member.

Reference to the accompanying drawing and the following descriptionthereof will serve to illustrate one embodiment of the improvedconstruction and arrangement as well as set forth additional operationalfeatures which may be obtained from the use of the overall system.

FIG. 1 of the drawing is a diagrammatic elevational view, partially insection, showing the assembly of a removable cylinder member within thehousing section and the provision of opposing nonle means for each sideof the resulting circular slot means.

FIG. 2 is a partial sectional view, somewhat enlarged, indicating aparticular form of noale construction for the device.

Referring now particularly to FIG. 1, there is indicated a housingmember 1 which has a predetermined sized circular opening 2 through anaxial portion thereof. The remaining axial extension of opening 2 is ofslightly lesser diameter and provided with an internally threadedsection 3 which in turn is adapted to receive an externally threadedportion encompassing an upper shank portion 4 of cylinder member 5. Thenon-threaded lower portion of the latter is of a predetermined diametersomewhat smaller than the opening 2 in housing 1 such that apredetermined width slot means 6 will exist between the external face ofcylinder section 5 and the internal face of the hole or opening 2 inhousing 1. The circular slot 6 will have a width generally correlatedwith the thickness of the types of tubing or piping, indicated as 7which will be inserted for test purposes and, more particularly, todetermine variations in thickness from desired standards. in otherwords, where thick wall tubing 7 is being tested in the device, therewill be a relatively thicker annulus than for thin wall tubing. Forexample, but not by way of limitation, the slot means 6 which may be ofthe order of about one-sixteenth inch for thin wall tubing andone-eighth inch or more in width for thick wall tubing or piping.

It will be noted that the housing 1 is provided with one air inlet meansfrom the internally threaded opening 8 and from the continuing drilledopening adapted to accommodate the inserted cylinder means 9 in turnterminating in a fluid outlet port or nozzle 10. The axially positionedcylinder member 5 with the threaded shank portion 4 is also providedwith an internally threaded opening ll, adapted for connection to a pipeor tubing section 21, and an axially drilled hole 12 which carries downthrough a major portion of cylinder section 5 as an axial passageway.From a mid-portion of the latter, there is a radially positioned drilledhole for a tube member 13 which, in turn, serves as a nozzle outletportion 14. The nozzle 14 is of the same size or dimension as the nozzleextremity or port means within the housing 1 whereby there can beopposing equivalently sized nozzles to in turn provide for the releaseof air streams to each side of the tubing 7 when it is inserted into theslot means 6. For purposes of accurate assembly, the threading means 3in housing 1 and on the matching external periphery of shank portion 4for the center cylinder member 5 shall be relatively flne," wherebythere can be close longitudinal adjustment with respect to nozzlemembers 9 and 13 and a resulting axial alignment of nozzle portions 10and 14. At the same time, it may be desirable to provide a notch means15 on a lower wall portion of opening 2 in housing 1 as well as notchmeans 16 on a lower external part of cylinder member 5 whereby thealignment of the notch means 15 and 16 will in turn assure the axialalignment of nozzle means 10 and 14.

In FIG. I of the drawing, there is also indicated diagrammatically airinlet means to the housing 1 from piping or tubing means 17 having a Tee18 such that a line 19 can in turn connect to a Tee member 20.Similarly, with respect to the shank portion 4 of cylinder member 5,there is piping means 21 having a Tee 22 in turn connecting with tubing23 that joins with the opposite end of Tee 20. From Tee 20, there istubing 24 shown connective with a suitable gauging member, such as theair column 25. The latter can be of a standard commercial constructionarranged to have air flow therethrough that can be discharged by way ofoutlet means 26 with control valve means 27. The air column will, inaddition, have internal float means 28 and a scale means 29 such thatthere can be a visual observation of variations in float level which, inturn,

will provide an indication of air flow rate through the column.

In operation, the air pressure to each of the air inlet tubings 17 and21 will be regulated so as to provide a uniform pressure and flow ratesuch that the back pressure and flow rate variations carrying back tothe nozzle means 10 and 14 and to the respective passageways will inturn vary the flow rates and pressures within lines 19 and 23 carryingto Tee member 20 whereby the averaged pressure and/or flow rage carryingthrough tube means 24 to air column 25 will, in turn, vary float member28 with respect to height along scale means 29. it is to be noted thatwith a uniform thickness for tubing 7 between air outlet ports 10 and14, and within slot means 6, will not vary pressure or flow rate at theair column 25 inasmuch as there is an averaging pressure between the twononles to each face of the tubing 7. Also, the actual centering of thetubing within the hole or slot means 6 is not required inasmuch as thetwo nozzles compensate for each other. However, the float 28 will changeposition where there is a variation in thickness of tubing regardless ofcentering in the slot. Preferably, in the utilization of the apparatus,the tubing 7 will be rotated within the slot means 6 and as long asthere are no variations in wall thickness, there will be no changes inthe float readings in air column 25. However, where there is greaterthickness for a portion of the tubing 7, there will be a greater backpressure through the nozzle means to the respective air inlet means andan increased air flow rate indicated at air column 25. Conversely, wherethere is a thinner than normal portion of tube wall 7, then there willbe a greater flow rate through the nozzle means of the device and acorresponding decrease in flow rate indicated at air column 25. Withrespect to the air column itself, the scale will be calibrated tocorrespond with variations in thickness for a particular tube wallthickness to be utilized in the device, with the calibration being suchas to establish upper and lower float positioning by virtue of a valve27 adjustment at the top of the air column as well as by regulator means30 at the lower end of the column. Operational experience has shown thatwith small diameter tubings of the order of five-eighths inch O.D. therecan be variations in wall thickness of the order down to approximatelyonefourth of 0.00l of an inch.

With respect to particular construction details, it will be noted inFIG. 1 of the drawing that a set screw means 31 may be provided throughthe housing means 1 so as to pemtit the screw to contact the exteriorface of cylinder section 5 and hold it at a desired location after therehas been proper axial alignment of the two opposing noule means 10 and14. In addition, there will be noted that the lower end portion ofcylinder section 5 has been beveled or chamfered at 32 while theexternal periphery of the opening or hole means 2 has been beveled at33. Thus, there is provided an easy insertion for the various tubularmembers 7 into the narrow slot means 6 for each thickness variation testoperation.

With reference to FIG. 2 of the drawing, there has been an enlargedsectional view shown for the tube members 9 and 13 and the provision ofa recessed area around each outlet port section of each nozzle means. Inother words, it will be noted that member 9 has been inserted by pressfitting into a drilled hole portion of housing 1 and that a smalldiameter end portion is provided such that there is a resulting recessor opening around the latter at 34. With respect to tube member 13 incylinder section 5, there can also be the press fit of member 13 into aradially drilled hole connective with the axial hole or opening 12whereby air flow from the latter can pass radially outwardly in thecylinder member out the slot member 6. However, in connection with theoutlet port zone around nozzle portion 14, there is provided an enlargedopening 35 whereby there is depression or recessed area around theoutlet port portion of nozzle 14. As a result, the two opposing nozzles10 and 14 will have some recessed spaces therearound to permit uniformair flow outwardly in each case into the slot area 6. It is to befurther noted that the inside diameter of each of the tube means 9 and13 shall be equivalent whereby there will be resulting equivalent nozzleaction" from each side of the slot 6 and against each face of the tubingwhich will be inserted into the slot means.

As hereinbefore noted, the removable construction for the cylindermember 5, with threaded shank section 4, permits the removability andinterchangeability of cylinder sections in the tube testing device. inother words, where thick wall tubings or pipes are to be inserted in thedevice for measuring variations in wall thickness, then a small diametercylinder section 5 can be utilized and provide a greater slot width forthe annular slot means 6 without any changes in the housing or blockportion 1. Variations in methods of alignment or positioning thecylinder member with respect to the housing member so as to obtainaccurate axial alignment with the two opposing nozzles may be providedwithin the scope of the present invention. Also, variations in actualdesign and placement of nonle members themselves will be obvious tothose skilled in the art and should be considered within the generalbroad scope of the present invention which provides for theadjustability and removability for a central cylinder section within adevice adapted to check or gauge tube wall measurements.

Still further, it is not intended to limit the present system to the useof a single air column only, inasmuch as other types of air columns,flow meters, pressure gauge means, etc., may well be used after propercalibration to effect the desired variations in flow measurement andindications of wall thickness differences. In connection with automaticread-out systems, it is generally preferable to utilize pressure gaugingwhere the instrumentation is sensitive to air pressure rather than toflow rates.

We claim as our invention:

1. An apparatus system for measuring variations in thickness of tubing,which comprises in combination, a housing with a circular slot meanstherein from one end thereof for accommodating the non-touchinginsertion of tubing to be measured for thickness variations, said slotmeans formed by the positioning of a removable cylinder member in acircular hole in said housing which is of predetermined diameter largerthan said cylinder member, a fluid outlet port provided in and throughsaid housing to discharge in said slot means, a fluid outlet port fromsaid cylinder member directly opposite first said outlet port and ofequal size as the latter, means in cooperative association with saidhousing and said cylinder member enabling radial alignment of saidrespective outlet ports, fluid supply means to each of said opposingports, a pressure tap means branching from each of said fluid supplymeans, with each of the pressure tap means being joined and a singleconduit means from the juncture thereof connective to a gauging meansproviding a reading correlatable to the thickness of material insertedin said circular slot means.

2. The apparatus system of claim 1 further characterized in that saidcylinder member has a threaded shank portion and said housing has athreaded section adapted to receive the latter, whereby an adjustablethreaded engagement is provided between said housing and said cylindermember.

3. The apparatus system of claim 1 further characterized in that saidfluid supply means for said cylinder member includes a fluid passagewayaxially through a portion of the cylinder member from the end oppositesaid slot means and a radial passageway from the latter to terminate atthe exterior face of said cylinder member as said fluid outlet porttherefrom.

4. The apparatus system of claim 1 further characterized in that both ofsaid fluid outlet ports have recessed areas of equal size around theirouter extremities and the inside and outside diameters are equal size,whereby to provide equivalent nozzle effects for the discharge of an airstream from each port.

5. The apparatus system of claim 4 still further characterized in thateach of the fluid outlet port means through said housing and through aradial portion of said cylinder member are provided by a tubular formnozzle member provided within a drilled passageway for respectively thehousing and said cylinder member.

6. The apparatus system of claim 1 further characterized in that saidgauging means connective with said single conduit means connects with acalibrated air column having a float member therein that is adjusted tofloat along a vertical scale responsive to variations in wall thicknessfor the tubing in the slot means which, in turn, will provide variationsin flow rate to said air column.

7. An apparatus system for measuring variations in thickness of tubing,which comprises in combination, a housing with a circular slot meanstherein from one end thereof for accommodating the non-touchinginsertion of tubing to be measured for thickness variations, said slotmeans formed by the positioning of a removable cylinder member in acircular hole in said housing which is of predetermined diameter largerthan said cylinder member, a fluid outlet port provided in and throughsaid housing to discharge in said slot means, a fluid outlet port fromsaid cylinder member directly op posite first said outlet port and ofequal size as the latter, a positioning mark in longitudinal alignmentwith the center of the outlet port for said housing and a positioningmark in longitudinal alignment with the center of the fluid outlet portfor said cylinder member, whereby the alignment of said positioningmarks with one another will in turn efi'ect radial alignment betweensaid fluid outlet ports, fluid supply means to each of said opposingports, a pressure tap means branching fonn each of said fluid supplymeans, with each of the pressure tap means being joined and a singleconduit means from the juncture thereof connective to a gauging meansproviding a reading correlatable to the thickness of material insertedin said circular slot means.

1. An apparatus system for measuring variations in thickness of tubing,which comprises in combination, a housing with a circular slot meanstherein from one end thereof for accommodating the non-touchinginsertion of tubing to be measured for thickness variations, said slotmeans formed by the positioning of a removable cylinder member in acircular hole in said housing which is of predetermined diameter largerthan said cylinder member, a fluid outlet port provided in and throughsaid housing to discharge in said slot means, a fluid outlet port fromsaid cylinder member directly opposite first said outlet port and ofequal size as the latter, means in cooperative association with saidhousing and said cylinder member enabling radial alignment of saidrespective outlet ports, fluid supply means to each of said opposingports, a pressure tap means branching from each of said fluid supplymeans, with each of the pressure tap means being joined and a singleconduit means from the juncture thereof connective to a gauging meansproviding a reading correlatable to the thickness of material insertedin said circular slot means.
 2. The apparatus system of claim 1 furthercharacterized in that said cylinder member has a threaded shank portionand said housing has a threaded section adapted to receive the latter,whereby an adjustable threaded engagement is provided between saidhousing and said cylinder member.
 3. The apparatus system of claim 1further characterized in that said fluid supply means for said cylindermember includes a fluid passageway axially through a portion of thecylinder member from the end opposite said slot means and a radialpassageway from the latter to terminate at the exterior face of saidcylinder member as said fluid outlet port therefrom.
 4. The apparatussystem of claim 1 further characterized in that both of said fluidoutlet ports have recessed areas of equal size around their outerextremities and the inside and outside diameters are equal size, wherebyto provide equivalent nozzle effects for the discharge of an air streamfrom each port.
 5. The apparatus system of claim 4 still furthercharacterized in that each of the fluid outlet port means through saidhousing and through a radial portion of said cylinder member areprovided by a tubular form nozzle member provided within a drilledpassageway for respectively the housing and said cylinder member.
 6. Theapparatus system of claim 1 furtheR characterized in that said gaugingmeans connective with said single conduit means connects with acalibrated air column having a float member therein that is adjusted tofloat along a vertical scale responsive to variations in wall thicknessfor the tubing in the slot means which, in turn, will provide variationsin flow rate to said air column.
 7. An apparatus system for measuringvariations in thickness of tubing, which comprises in combination, ahousing with a circular slot means therein from one end thereof foraccommodating the non-touching insertion of tubing to be measured forthickness variations, said slot means formed by the positioning of aremovable cylinder member in a circular hole in said housing which is ofpredetermined diameter larger than said cylinder member, a fluid outletport provided in and through said housing to discharge in said slotmeans, a fluid outlet port from said cylinder member directly oppositefirst said outlet port and of equal size as the latter, a positioningmark in longitudinal alignment with the center of the outlet port forsaid housing and a positioning mark in longitudinal alignment with thecenter of the fluid outlet port for said cylinder member, whereby thealignment of said positioning marks with one another will in turn effectradial alignment between said fluid outlet ports, fluid supply means toeach of said opposing ports, a pressure tap means branching form each ofsaid fluid supply means, with each of the pressure tap means beingjoined and a single conduit means from the juncture thereof connectiveto a gauging means providing a reading correlatable to the thickness ofmaterial inserted in said circular slot means.